Various types of 3D simulator apparatus that are used in applications such as 3D games or piloting simulators for aircraft or other moving bodies are known in the art. With such a 3D simulator apparatus, image information relating to a 3D object 300 shown in FIG. 25A his previously stored within the apparatus. In this case, the 3D object 300 depicts an element such as part of scenery that can be seen by a player 302 as if through a screen 306. The image information for the 3D object 300 that depicts this scenery element is displayed as a pseudo-3D image 308 on the screen 306, by perspective projection conversion on the screen 306. The player 302 specifies operations such as rotation or translation through a control Panel 304, and this apparatus performs predetermined 3D computation processing on the basis of the resultant operating signals. More specifically, computations are first performed to determine whether a change has occurred, such as a change in the viewpoint position or direction of gaze of the player 302 or a change in the position or orientation of a moving body in which the player 302 is sitting, as specified by these operating signals. Computations are then performed to determine how the image of the 3D object 300 can be seen on the screen 306, in accordance with this change such as a change in viewpoint position or direction of gaze. The above computations are performed in real time, following the actions of the player 302. This makes it possible for the player 302 to see any change in the scenery due to a change in the player's own viewpoint position or direction of gaze or a change in the position or orientation of the moving body in which the player is sitting as a pseudo-3D image in real time, to simulate the experience of a virtual 3D space.
An example of a display screen formed by a 3D simulator apparatus as described above is shown in FIG. 25B.
In such a driving game or simulator, the realism of the game or simulation can be enhanced by forming a sub-screen depicting an element such as a rear-view mirror or a side mirror on a display screen (main screen) as shown in FIG. 25B.
To further enhance the feeling of realism in the game or other simulation in this case, it is preferable that a pseudo-3D image with a degree of realism that is similar to that of the main screen is displayed on the sub-screen, such as the rear-view mirror.
However, if the pseudo-3D image is displayed on the sub-screen with the same degree of realism as on the main screen, computations for forming this sub-screen will also be necessary. Unfortunately, a simulator apparatus of this type has a limitation in that the computations for synthesizing the images should be completed within one frame, which could take 1/60 second. Therefore, if it is thought necessary to synthesize a pseudo-3D image for the sub-screen as well, as described above, problems arise in that the computations cannot be completed in time, phenomena such as drop-outs occur in the data to be displayed on the main screen, and thus the quality of the image deteriorates.
This invention was devised in order to solve the above technical problems and has as its objective the provision of a 3D simulator apparatus and an image synthesis method that can not only create an extremely realistic sub-screen on a main screen, but also ensures that the formation of this sub-screen hardly affects the image synthesis processing for the main screen.